Technological innovations and halachai think you misunderstood the issue - the machmirim here are referring to when one can see something but is not actually discernable as a bug - if you can see it with a microscope then one should be machmir (many dispute this though). but almost no one holds if one can't see anything w/o use of microscope - it is not considered to exist!! see this thorough article -ohr.edu/this_week/insights_into_halacha/5043